Ministers (who have not elected voluntary withholding) and self-employed workers must file their third quarterly estimated federal tax payment for 2016 by this date (a similar rule applies in many states to payments of estimated state taxes). Nonminister employees of churches that filed a timely Form 8274 (waiving the church’s obligation to withhold and pay FICA taxes) are treated as self-employed for Social Security, and as a result, are subject to the estimated tax deadlines with respect to their selfemployment (Social Security) taxes unless they ask their employing church to withhold an additional amount of income taxes from each paycheck (use a new Form W-4 to make this request) that will be sufficient to cover self-employment taxes.